What is the voltage of a Subaru battery?

In a nutshell, Subaru’s conventional gasoline and hybrid models use a standard 12-volt battery to start the engine and run accessories, while Subaru’s all-electric Solterra uses a high‑voltage traction battery around 355 volts nominal. Exact figures vary by model and state of charge, so check the owner’s manual for specifics.

12-volt electrical system in most Subaru models

The majority of Subaru vehicles rely on a 12-volt lead-acid battery to power the starter motor, lights, and electronics when the engine is off. The following points summarize what you need to know about this system.

• The resting voltage of a healthy 12-volt battery is typically around 12.6 volts when fully charged.


• While the engine or a charger is running, the alternator or DC‑DC converter raises the system voltage to about 13.8–14.4 volts to maintain charging.


• Battery health can vary with climate and usage; common replacement intervals are roughly 3–5 years in many driving conditions.


• Voltage below about 12.0 volts at rest can indicate a weak or discharged battery and may require charging or replacement.


• Battery size and terminal arrangement vary by model; consult the owner’s manual or a parts professional for the correct 12V battery for your Subaru.

In summary, the 12‑volt battery is the standard, everyday electrical backbone for most Subaru models, independent of whether the vehicle is gasoline, hybrid, or otherwise non‑electric.

High-voltage battery systems in Subaru electrified models

Electric and hybrid Subarus use a high‑voltage traction battery to power propulsion. These packs operate far above the 12‑volt system and require proper safety procedures and equipment when handling. The following details apply to Subaru’s modern electrified offerings, including the Solterra.

Nominal voltage and pack characteristics

• The high‑voltage traction battery in Subaru’s BEV/Hybrid platforms has a nominal voltage in the mid‑hundreds of volts, typically around 355 volts for models built on the Toyota e‑TNGA architecture (Solterra and related platforms).


• Pack energy capacity is in the tens of kilowatt‑hours range (for Solterra, commonly discussed as around 60–64 kWh usable, with a larger gross pack size depending on market/specification).


• The high‑voltage system is designed for propulsion, with the DC‑DC converter charging the 12‑V auxiliary battery from the high‑voltage pack.

In short, while the 12‑volt battery remains crucial for routine vehicle functions, the Solterra and other electrified Subarus rely on a high‑voltage traction battery that operates at roughly 355 volts and stores tens of kilowatt‑hours of energy for driving.

Charging and safety considerations

• DC fast charging for Subaru BEVs typically tops out around 150 kW, allowing rapid replenishment of the high‑voltage pack on compatible networks.


• AC charging (Level 2) is commonly supported at several kilowatts (often around 6.6 kW, depending on charger and market), suitable for overnight home charging.


• High‑voltage components are shielded and interlocked; service access should be performed only by qualified technicians using proper safety procedures and tools.


• Never attempt to measure or troubleshoot high‑voltage packs with a standard 12‑volt meter or without appropriate PPE and training.

Overall, the high‑voltage system in Subaru’s electrified models is designed to be safe and efficient, but it is fundamentally different from the conventional 12‑volt battery and requires appropriate handling and charging equipment.

Summary

Subaru uses two distinct voltage ecosystems: a 12‑volt system for traditional engines and accessories, and a high‑voltage traction battery for electric/hybrid models like the Solterra. The 12‑volt battery typically sits around 12.6 V when healthy and is charged to about 13.8–14.4 V by the alternator or DC‑DC converter. The Solterra and similar BEV/hybrid platforms employ a nominal high‑voltage pack around 355 V with tens of kilowatt‑hours of energy storage, supporting rapid DC charging and everyday EV operation. For exact specifications on your vehicle, consult the owner’s manual or a Subaru service center.

How many volts is a Subaru battery?

A healthy Subaru battery should read between 12.6 and 12.8 volts with the engine off, indicating a full charge. With the engine running, a healthy charging system should show a voltage between 13.7 and 14.7 volts, confirming the alternator is working correctly. A voltage below 12.4V with the engine off suggests the battery needs charging, while a reading consistently below 12V while the engine is running indicates a problem with the alternator.
 
This video explains how to check the battery voltage and other information with a multimeter: 1mOBD InsightsYouTube · Feb 13, 2025
When the engine is off

• 12.6V to 12.8V: Fully charged and healthy. 
• 12.4V to 12.5V: About 75% charged; can still start the car, but may need a charge. 
• Below 12.4V: May need charging, and if it drops below 12.2V, it may indicate the battery is bad or unable to hold a charge. 

When the engine is running

• 13.7V to 14.7V: Normal charging range, meaning the alternator is working to charge the battery. 
• Below 13.7V: The alternator is not charging the battery properly and may need to be serviced. 
• Above 14.7V: The alternator is overcharging the battery, which can damage it. 

How to check your battery voltage

• Method 1: Using the Subaru display
  • Turn on the car without starting the engine (press the "Power" button twice while your foot is off the brake). 
  • Hold down the "Info" button on the touchscreen. 
  • While holding "Info," turn the headlights on and off three times. 
  • The "Diagnosis Menu" should appear. Navigate to "Menu" -> "Display Check" -> "Vehicle Signal Check" to see the 12V battery voltage. 
• Method 2: Using a multimeter
  • Place the red probe on the positive (+) battery terminal and the black probe on the negative (-) terminal. 
  • To check if the engine is charging the battery, start the car and take another reading. 

Is 12.2 volts a dead battery?

No, 12.2 volts is not necessarily a dead battery, but it is low and indicates the battery is partially charged (around 50–60%) and may struggle to start your car. A fully charged battery should read about 12.6 volts or higher when the engine is off. You should recharge the battery to prevent damage and shorten its lifespan. 
You can watch this video to learn about checking your car battery's voltage: 39sTorqueCarsYouTube · Oct 31, 2023
Understanding your battery's voltage

• Fully charged: A healthy, fully charged battery will show a resting voltage of about 12.6 volts or higher. 
• Partially charged: A reading of 12.2 volts suggests the battery is around 50-60% charged and should be recharged. Running it at this low level for extended periods can reduce its lifespan. 
• Discharged or failing: A reading below 12.0 volts indicates a discharged or failing battery, and a reading of 10.5 volts is considered fully discharged. 

What to do next

• Recharge the battery: Drive your car for about 30 minutes, or use a battery charger, to bring the voltage back up. 
• Monitor the voltage: After charging, test the battery again. If the voltage is still low, or if it fails to hold a charge, the battery may need to be replaced. 

Is 11.7 volts a dead battery?

Partially Discharged: A battery showing around 12.1 volts is approximately 50% charged, while a reading of about 11.7 volts indicates it's around 25% charged. Fully Discharged: A reading of 10.5 volts or lower usually indicates a dead or fully discharged battery.

What voltage is too low for a car battery?

A car battery is too low if it reads below 12.0 volts when the engine is off; this is considered fully discharged and needs to be recharged. A reading between 12.0 and 12.4 volts indicates the battery is partially charged and should be recharged soon, as running it at this level for too long can decrease its lifespan. If the voltage drops to or below 10.5 volts, the battery is essentially scrap and will not be able to start the engine.
 
This video explains what a 12-volt car battery should read when the engine is off: 38sMechanic MindsetYouTube · Mar 11, 2021
Voltage and charge levels (engine off) 

• $12.6$V or higher: Fully charged 
• $12.4$V: Approximately 60% charged 
• $12.0$V to $12.4$V: Partially discharged, needs recharging 
• Below $12.0$V: Fully discharged or "flat" 
• $10.5$V or lower: Critically low, likely damaged and considered "scrap" 

What to do if your battery is low

• Recharge the battery: If the voltage is between 12.0V and 12.4V, a full charge can restore it. 
• Check for problems: If the battery is low again after charging, it could be due to a number of issues: 
  • Alternator problems: The alternator may not be charging the battery correctly. 
  • Parasitic drain: Something in the car might be drawing power even when it's off. 
  • Old age: An old battery is more sensitive to low voltage and may be unable to hold a charge properly. 
• Consider replacement: If the battery voltage consistently falls below 12.0V, or if it shows other signs of failure (like taking multiple attempts to start), it's likely time to replace it. 

You can watch this video to learn how to check your car battery voltage with a multimeter: 1mHSZ GarageYouTube · Aug 22, 2022